There is a need in industry today to provide a chemical solution that is ready to use when mixed and that is made from solid cast chemical. Solid cast chemical is essentially a chemical that is in solid form and cast in a preferably pliable, plastic container; it is effectively a bar of soap in a plastic container. Removal is typically done by dissolving the detergent in place in the container with a jet of water.
There are a number of advantages to using solid cast chemical as compared to liquid chemical. The first is safety. Since the chemical is cast inside of a container it is virtually impossible for personnel to come in contact with the chemical until it has been diluted. The U.S. Department of Transportation recognizes such chemical as safe to ship. If there is an accident, there is no liquid spillage to contaminate the ground water in the immediate area. The containers, even if cracked by the accident, retain the chemical and may simply be retrieved.
The concentration that is possible with solid cast chemical provides additional advantages. Such detergent is typically 100% active material as opposed to liquid which is between 40% and 5% active, with the remainder being water. A single capsule of solid chemical can do the same work as six to seven gallons of a typical liquid. A related advantage is the compactness of solid chemical that provides benefits when storing the chemical, shipping chemical, and when handling the chemical. The dramatic reduction in storage space is especially attractive to relatively small commercial establishments such as gas stations and fast food restaurants that have very little space to devote to storing cleaning supplies. Freight costs are also dramatically reduced since the cost of shipping water is eliminated. Other handling costs are also reduced since, for equal cleaning potential, substantially less weight and volume is being handled as compared to liquid chemical.
Another advantage of solid cast chemical is that it has an essentially indefinite shelf life. Very little can occur that can change the character of the product over time.
Solid cast chemicals are more environmentally sound than liquids. Studies have shown that “bag-in-a-box” and five gallon pail packaging of liquid chemicals actually have approximately four to five ounces of chemicals left when the package is considered empty and therefore is discarded. Raw chemicals are accordingly dumped into landfills when liquid chemical packages are discarded. Solid cast chemicals use approximately one sixth the volume of empty containers as a liquid system of equal cleaning capacity, and solid cast chemical containers are usually thoroughly rinsed of all chemical by water jet action before being discarded or recycled.
A further requirement of chemical dispensers is that the dispenser should preferably provide a ready to use solution. This requirement is a major concern for many commercial establishments. The portion of the labor pool that is utilized for cleaning functions is typically the lower skilled and less educated portion. Training of these employees is difficult and expensive. The fact that the solution is ready to use minimizes the training that is required for proper usage.
Another aspect of the training issue is that the dispenser should have a minimum number of controls and control operations necessary to obtain a container of properly mixed detergent solution. Ideally, the turning of a single valve would provide the solution.
Reliability is another desirable characteristic of a chemical dispenser. A minimum number of moving parts should be provided to minimize maintenance. The dispenser should also be small and be capable of being mounted on the wall, since the storage area for cleaning equipment in most commercial establishments is very small.
A further concern is that the chemical solution that is formed within the dispenser be isolated from the water supply, which in most cases is the water supply of the local municipality. There is considerable concern that in the event of a backup of the chemical solution in the dispenser, the chemical may be drawn into the water supply through the various plumbing that is in the dispenser. Accordingly, means must be devised to ensure that such contamination does not occur.
In the past, liquid chemical dispensers have been available that dispense a ready to use detergent solution. Additionally, solid cast chemical dispensers have been available. Drawing the concentrated chemical solution from the dispenser has proved to be a problem. When in the concentrated form, the chemical solution does not tend to flow freely and has a tendency to accumulate in the dispenser. If the solution remains in the bowl after water is turned off. The solution tends to solidify, thereby clogging the bowl
In view of the foregoing, it would be a decided advantage to have a chemical dispenser that utilizes a solid cast chemical and that can positively discharge a ready to use concentration of chemical solution. The design should provide for transporting the solution over significant distances and at heights that exceed the height of the dispenser. In order to effect this, it would be helpful if the chemical solution was forcefully expressed for use.
U.S. Pat. No. 5,846,499, owned by the assignee of the present application, in part met the aforementioned needs. Flow from the bowl of the dispenser was enhanced, but was not forcefully expressed. Flow from the dispenser could not terminate at a height higher than the height of the dispenser and the flow must terminate close to the dispenser in order to ensure that the bowl was adequately purged.